Use a branch-If-equal beq , something like this :
beq $t0 $t1 if
#here your else block
j done
if : 
#here your if block 
done:
Here is a link to a MIPS instruction reference.
solved C to MIPS How will i convert an if else statement [closed]
 
Use a branch-If-equal beq , something like this :
beq $t0 $t1 if
#here your else block
j done
if : 
#here your if block 
done:
Here is a link to a MIPS instruction reference.
solved C to MIPS How will i convert an if else statement [closed]